1. Field of the Invention
The present invention relates to a motor drive device having a safety stopping function, and more particularly to a motor drive device having a safety stopping function for stopping the motor when a part of human body is jammed, for example, by the movable part driven by the motor.
2. Description of Related Art
Hitherto, a motor drive device having a safety stopping function is used in various components of an automobile, such as a power window, a power seat, or a power trunk, and is designed to protect the human body by stopping the motor when part of the body is jammed by the window, the seat or the trunk driven by the motor.
The compartment of a vehicle of so-called one-box type represented by “mini-van” accommodates two or three rows of seats. In such vehicle, the sea layout can be changed depending on the purpose of use or application by the passengers. In a typical example, the backrests of the seats of the second row or third row are tilted forward, and the backside of the backrests of the second row is used as a table.
When the backrests of the seats are tilted forward (folded), and the backside is used as a table, to raise the seats back to a sitting position, the car door is opened from the flank, and the backrests must be manually raised by the passenger. Such manipulation consumes time and labor and is very disturbing. In such a case it is desired to install a backrest tilting device for raising the backrests by a switch operation from a remote position.
Prior art 1 discloses a motor control device of a motor for driving the power window or the like, in which the current change amount per unit time of the motor is monitored, and jamming of part of the body or other objects by the power window is detected. Prior art 2 discloses a vehicle seat device for detecting jamming by pulse period of a motor. Prior art 3 discloses a jamming detection method in which jamming is detected at high accuracy by using a reference threshold by adding a preliminarily calculated constant to the motor driving current. Prior art 4 discloses a foreign matter jamming detection device in which a jamming detection region is determined, the pulse change amount in the region is monitored when any object gets into the region, and jamming is detected when the change amount exceeds a normal reference value.
[Prior art 1] Japanese Patent No. No. 3181461 is incorporated herein by reference.
[Prior art 2] JP2004-268757 A is incorporated herein by reference.
[Prior art 3] JP2005-3330703 A is incorporated herein by reference.
[Prior art 4] JP2006-82626 A is incorporated herein by reference.